You enter an amount, see a quote and confirm the swap, but the final amount you receive is slightly different. In most cases, this comes down to two related ideas: price impact and slippage. Understanding the difference helps you choose better trade sizes, pairs and timing, especially in volatile markets.
What Is Price Impact?
Price impact is how much your own trade moves the price. On automated market maker (AMM) exchanges, prices are set by the ratio of tokens in a liquidity pool. When you buy a token from the pool, you remove some of it and add the other token, which shifts the ratio and makes each additional unit more expensive.
A simple way to think about it:
- In a deep pool with lots of liquidity, a small trade barely changes the ratio, so price impact is low.
- In a shallow pool, the same trade changes the ratio a lot, so price impact is high.
- The larger your trade relative to the pool, the larger the price impact.
Price impact is known before you trade. Most swap interfaces show it as a percentage next to the quote.
What Is Slippage?
Slippage is the difference between the price you expected when you submitted a trade and the price at which it actually executes. It happens because markets keep moving between the moment you see a quote and the moment your transaction is processed. Other trades may land first, or the market price may change during network congestion.
Slippage can be negative, meaning you receive less than quoted, or positive, meaning you receive more. During fast markets, negative slippage is more common simply because prices move quickly.
Price Impact vs Slippage
- Price impact is caused by your trade size relative to available liquidity.
- Slippage is caused by price movement between quote and execution.
- Price impact is visible before you confirm, while slippage is only known after execution.
- Both reduce the amount you receive and add to your total trading cost alongside fees.
What Is Slippage Tolerance?
Many decentralized exchanges let you set a slippage tolerance, which is the maximum price change you accept before a trade is cancelled. For example, with a 0.5% tolerance, the trade fails if the execution price is more than 0.5% worse than the quote.
Choosing the setting involves a trade-off:
- A tolerance that is too low can cause transactions to fail in volatile markets, and on some networks failed transactions still cost gas.
- A tolerance that is too high can expose you to a worse fill and makes your trade a more attractive target for front-running bots.
- Major pairs with deep liquidity usually need lower tolerance than small or newly launched tokens.
What Is Front-Running and MEV?
On public blockchains, pending transactions can be visible before they are confirmed. Some bots try to profit from this, a practice often called maximal extractable value (MEV). In a "sandwich" attack, a bot buys just before your trade and sells just after it, pushing your execution price toward the edge of your slippage tolerance. Keeping tolerance reasonable and avoiding very large trades in thin pools reduces this risk.
What Affects Your Final Rate
- Liquidity depth of the pair on the chosen network
- Trade size relative to that liquidity
- Market volatility at the time of the trade
- Network congestion and confirmation speed
- Trading and network fees
- Routing, meaning whether the swap goes directly between two tokens or through intermediate assets
Practical Tips to Reduce Slippage and Price Impact
- Check the price impact shown before confirming. If it is high, consider a smaller amount.
- Split large orders into several smaller swaps when liquidity is thin.
- Prefer widely traded pairs, such as major tokens against USDT or USDC, which usually have deeper liquidity.
- Avoid trading during sharp price moves or major news releases, such as inflation data, if you are not in a hurry.
- Compare the same pair across different networks, since liquidity and fees vary from chain to chain.
- Always review the minimum amount you will receive, if the interface shows it, before you confirm.
A Quick Example
Suppose you want to swap a token worth $10,000 in a pool that holds only $100,000 of liquidity. Your trade is 10% of the pool, so price impact will be significant and you may receive noticeably less than the headline price. Swapping the same $10,000 in a pool with $10 million of liquidity represents just 0.1% of the pool, so price impact would be minimal. This is why the same token can have very different effective prices depending on where and how you trade it. The numbers here are illustrative only.
The Bottom Line
Price impact comes from your trade size, slippage comes from market movement, and both affect what you actually receive. Checking liquidity, trade size, timing and the quoted minimum output before you confirm is one of the simplest ways to improve your results. When you swap supported assets on AviorSwap, which lists 17+ networks, review the quote, fees and final amount before each trade.